package com.chen.common.config;

import com.netflix.client.config.IClientConfig;
import com.netflix.loadbalancer.AbstractLoadBalancerRule;
import com.netflix.loadbalancer.ILoadBalancer;
import com.netflix.loadbalancer.Server;

import java.util.List;
import java.util.concurrent.ThreadLocalRandom;

/**
 * @ClassName
 * @Description: 自定义随机规则
 * @Author:
 * @Date: Created in 17:49 2022/6/5
 */
public class MyRandomRule extends AbstractLoadBalancerRule {

    /**
     *   每个服务访问 5 次，换下一个服务
     *  total 默认 0 ，如果 = 5 ，我们指向下一个服务节点
     *  index 默认0 ，如果 total = 5 ，index+1
     */
    private int total = 0;  //被调用的次数
    private int currentIndex = 0;   //当前是谁在提供服务

//    @SuppressWarnings({"RCN_REDUNDANT_NULLCHECK_OF_NULL_VALUE"})
    public Server choose(ILoadBalancer lb, Object key) {
        if (lb == null) {
            return null;
        } else {
            Server server = null;

            while(server == null) {
                if (Thread.interrupted()) {
                    return null;
                }
                //获得活着的服务
                List<Server> upList = lb.getReachableServers();
                //获得全部的服务
                List<Server> allList = lb.getAllServers();
                int serverCount = allList.size();
                if (serverCount == 0) {
                    return null;
                }
//                //生成区间随机数
//                int index = this.chooseRandomInt(serverCount);
//                //从活着的服务中随机获取某一个
//                server = (Server)upList.get(index);
//              =========================================================
                if(total<5){
                    server = upList.get(currentIndex);
                    total++;
                }else{
                    total = 0;
                    currentIndex++;
                    if(currentIndex>upList.size()){
                        currentIndex = 0;
                    }
                    server = upList.get(currentIndex);  //从活着的服务中，获取指定的服务来进行操作
                }
//              ========================================================
                if (server == null) {
                    Thread.yield();
                } else {
                    if (server.isAlive()) {
                        return server;
                    }
                    server = null;
                    Thread.yield();
                }
            }
            return server;
        }
    }

    protected int chooseRandomInt(int serverCount) {
        return ThreadLocalRandom.current().nextInt(serverCount);
    }

    @Override
    public void initWithNiwsConfig(IClientConfig iClientConfig) {

    }

    @Override
    public Server choose(Object key) {
        return choose(getLoadBalancer(), key);
    }
}
